1. Technical Field
The present invention relates generally to logical partitioning, and more particularly to testing of partitioning I/O subsystem adherence to proper logical partitioning I/I rules.
2. Description of Related Art
Logical partitioning is a system of taking a computer's total resources—processors, memory and storage—and splitting them into smaller units that each can be run with its own instance of the operating system and applications. Logical partitioning, which requires specialized hardware circuits, is typically used to separate different functions of a system, such as Web serving, database functions, client/server actions or systems that serve multiple time zones and/or languages. Logical partitioning can also be used to keep testing environments separated from the production environments. Since the partitions in effect act as separate physical machines, they can communicate with each other.
Some systems (IBM systems, for example) use firewalls that support logical partitioning. In a partitioned system, there are rules that must be followed by all I/O (input/output) operations from the I/O adapter. These rules include: (1) I/O adapters should be able to do DMA (Direct Memory Access) to all the system memory regions allocated to the partition to which they are assigned; (2) I/O adapters should not be able to do DMA to those system memory areas that do not belong to the partition to which they are assigned; (3) Each I/O adapter's parent (either PCI-to-PCI bridge (PPB) or PCI-to-Host bridge (PHB)) must contain the ‘ibm,dma-window’ property. The I/O adapter can throw only those bus addresses on the bus that lie in the address range as defined in the ‘ibm, dam-window’ property of its parent; and (4) I/O adapters cannot use Dual Address Cycle (DAC).
LPAR (logical partition) I/O subsystems should adhere to the LPAR I/O rules. There often arise situations where these rules may not be followed, due to software or hardware problems. Misbehavior in one partition can lead to a crash in other partitions. Therefore, there is a need in the art for means to test firewalls between partitions.